Applies To:
  • CitectSCADA x.x
Summary:
Bacnet Driver goes Offline if the number of tags is more than 30.

Solution:
This happens in cases where the BACnet router may reject packets that are sent from CitectSCADA and does not return a error code back to CitectSCADA. The Default frame size for the BACnet driver packet in CitectSCADA is 1476 bytes and some BACnet routers do not accept a packet size this big so they may simply reject it without sending any error codes back.

This happens especially when you use Multiread or Multiwrite using the following parameters where the framesize is very big (as we do multiple reads and writes at the same time)

[BACNET]
USEREADMULTIPLE
USEWRITEMULTIPLE

1 is the default.

In order to identify the problem, you could use Wireshark and analyse the logs between the BACnet router and CitectSCADA. CitectSCADA's syslog.dat and BACnet.dat logs will simply show the problem as a timeout.

To fix the issue you can reduce the FrameSize using the parameter

[BACNET]
FrameSize

1476 is the default.
Keywords:
 BACnet, FrameSize

Attachments